Subject: [mg88907] how to determine the center or foci of an ellipse from a slope

From: John Kellerham <johnkellerham at yahoo.com>

Date: Wed, 21 May 2008 14:48:32 -0400 (EDT)

Hi guys,
I have a slope field (2d-array), which is defined
by ellipses (can be arbitrarily tilted), which all have the
same foci and center but different major and minor half axes.
In fact, I obtained the tangent at each point by measurements.
Does somebody have an idea on how to approach the problem
of finding the center or the foci of the ellipses? I think
there is no exact solution to the problem?
Best Regards,
Thomas